The quiet-BAC protocol specifies a 9:55 AM PT final coordination check, five minutes before the 10:00 AM silence window — this five-minute window serves multiple purposes: (1) last-chance confirmation that all seven participants are active, (2) resolution of any overnight issues (GA4 access, template availability), (3) final protocol reminder before the communication blackout — the five-minute buffer is designed to be long enough to catch problems but short enough that participants don't drift into pre-experiment coordination — it's a careful balance between preparation thoroughness and protocol purity